On Wed, 2023-09-13 at 02:06 -0700, syzbot wrote: > Hello, > > syzbot has tested the proposed patch but the reproducer is still triggering an issue: > general protection fault in d_path Is an IMA policy being loaded? Please include the boot command line. > general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f] > CPU: 0 PID: 5465 Comm: syz-executor.0 Not tainted 6.6.0-rc1-syzkaller-00004-g965067e2f71e #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 > RIP: 0010:__seqprop_spinlock_sequence include/linux/seqlock.h:275 [inline] > RIP: 0010:get_fs_root_rcu fs/d_path.c:244 [inline] > RIP: 0010:d_path+0x2f0/0x6e0 fs/d_path.c:286 > Code: 30 00 74 08 48 89 df e8 be 20 e1 ff 4c 8b 23 4d 8d 6c 24 48 49 81 c4 88 00 00 00 4c 89 eb 48 c1 eb 03 4c 89 ef e8 00 1e 00 00 <42> 0f b6 04 33 84 c0 0f 85 89 00 00 00 45 8b 7d 00 44 89 fe 83 e6 > RSP: 0018:ffffc90005056ec0 EFLAGS: 00010246 > RAX: be27ea831a7ad800 RBX: 0000000000000009 RCX: ffff88801c713b80 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: ffffc90005056fd0 R08: ffffffff82068d08 R09: 1ffffffff1d34ccd > R10: dffffc0000000000 R11: fffffbfff1d34cce R12: 0000000000000088 > R13: 0000000000000048 R14: dffffc0000000000 R15: ffff888076dcc000 > FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f4b67d70420 CR3: 0000000016f66000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > audit_log_d_path+0xd3/0x310 kernel/audit.c:2138 > dump_common_audit_data security/lsm_audit.c:224 [inline] > common_lsm_audit+0x7cf/0x1a90 security/lsm_audit.c:458 > smack_log+0x421/0x540 security/smack/smack_access.c:383 > smk_tskacc+0x2ff/0x360 security/smack/smack_access.c:253 > smack_inode_getattr+0x203/0x270 security/smack/smack_lsm.c:1271 > security_inode_getattr+0xd3/0x120 security/security.c:2153 > vfs_getattr+0x2a/0x3a0 fs/stat.c:206 > ovl_getattr+0x1b1/0xf70 fs/overlayfs/inode.c:174 > ima_check_last_writer security/integrity/ima/ima_main.c:171 [inline] > ima_file_free+0x2c3/0x560 security/integrity/ima/ima_main.c:203 > __fput+0x36a/0x910 fs/file_table.c:378 > task_work_run+0x24a/0x300 kernel/task_work.c:179 > exit_task_work include/linux/task_work.h:38 [inline] > do_exit+0x68f/0x2290 kernel/exit.c:874 > do_group_exit+0x206/0x2c0 kernel/exit.c:1024 > get_signal+0x175d/0x1840 kernel/signal.c:2892 > arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:309 > exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:168 > exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204 > __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] > syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:296 > do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7f2a67a7cae9 > Code: Unable to access opcode bytes at 0x7f2a67a7cabf. > RSP: 002b:00007f2a6875c178 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca > RAX: 0000000000000001 RBX: 00007f2a67b9bf88 RCX: 00007f2a67a7cae9 > RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f2a67b9bf8c > RBP: 00007f2a67b9bf80 R08: 00007fffba3690b0 R09: 00007f2a6875c6c0 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2a67b9bf8c > R13: 000000000000000b R14: 00007fffba21b880 R15: 00007fffba21b968 > </TASK> > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:__seqprop_spinlock_sequence include/linux/seqlock.h:275 [inline] > RIP: 0010:get_fs_root_rcu fs/d_path.c:244 [inline] > RIP: 0010:d_path+0x2f0/0x6e0 fs/d_path.c:286 > Code: 30 00 74 08 48 89 df e8 be 20 e1 ff 4c 8b 23 4d 8d 6c 24 48 49 81 c4 88 00 00 00 4c 89 eb 48 c1 eb 03 4c 89 ef e8 00 1e 00 00 <42> 0f b6 04 33 84 c0 0f 85 89 00 00 00 45 8b 7d 00 44 89 fe 83 e6 > RSP: 0018:ffffc90005056ec0 EFLAGS: 00010246 > RAX: be27ea831a7ad800 RBX: 0000000000000009 RCX: ffff88801c713b80 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: ffffc90005056fd0 R08: ffffffff82068d08 R09: 1ffffffff1d34ccd > R10: dffffc0000000000 R11: fffffbfff1d34cce R12: 0000000000000088 > R13: 0000000000000048 R14: dffffc0000000000 R15: ffff888076dcc000 > FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f4b67d70420 CR3: 0000000016f66000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > ---------------- > Code disassembly (best guess): > 0: 30 00 xor %al,(%rax) > 2: 74 08 je 0xc > 4: 48 89 df mov %rbx,%rdi > 7: e8 be 20 e1 ff call 0xffe120ca > c: 4c 8b 23 mov (%rbx),%r12 > f: 4d 8d 6c 24 48 lea 0x48(%r12),%r13 > 14: 49 81 c4 88 00 00 00 add $0x88,%r12 > 1b: 4c 89 eb mov %r13,%rbx > 1e: 48 c1 eb 03 shr $0x3,%rbx > 22: 4c 89 ef mov %r13,%rdi > 25: e8 00 1e 00 00 call 0x1e2a > * 2a: 42 0f b6 04 33 movzbl (%rbx,%r14,1),%eax <-- trapping instruction > 2f: 84 c0 test %al,%al > 31: 0f 85 89 00 00 00 jne 0xc0 > 37: 45 8b 7d 00 mov 0x0(%r13),%r15d > 3b: 44 89 fe mov %r15d,%esi > 3e: 83 .byte 0x83 > 3f: e6 .byte 0xe6 > > > Tested on: > > commit: 965067e2 ima: fix wrong dereferences of file->f_path > git tree: https://github.com/amir73il/linux ima-ovl-fix > console output: https://syzkaller.appspot.com/x/log.txt?x=109b00e8680000 > kernel config: https://syzkaller.appspot.com/x/.config?x=df91a3034fe3f122 > dashboard link: https://syzkaller.appspot.com/bug?extid=a67fc5321ffb4b311c98 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > Note: no patches were applied.
